CFD Approach to supercritical carbon dioxide brayton cycle components

Abstract

While various Brayton cycles have been studied, the supercritical carbon dioxide (S-CO2) Brayton cycle was identified as one of the promising candidates for a future power cycle since it has high cycle efficiency at moderate temperature range and can be realized with compact components and simple layout. To develop an efficient S-CO2 cycle, the major technical challenge exists in the design of cycle components. In this thesis, CFD analysis of S-CO2 centrifugal compressor and PCHE (Printed Circuit Heat Exchanger) are presented. The numerical results of S-CO2 compressor were compared to the experimental data obtained from S-CO2 Pressurizing Experiment (SCO2PE) facility. A three dimensional mesh was produced by utilizing a compressor full geometry provided by compressor manufacturer. A property table of CO2 was generated by an in-house code and implemented to the CFD code. The compressor efficiency and pressure ratio of S-CO2 compressor were investigated. To design a PCHE in wide Reynolds number range, important information such as local friction factor and Nusselt number are required. Since the PCHE utilizes micro channel technology it is very difficult to measure the local parameters inside the channels. Therefore, numerical investigation to recover this information is essential. The main purpose of this study is to check if pre-existing set of correlations can successfully applied to the PCHE design and provide a conservative component design for the nuclear appli-cation.